Hydroelectric is not emission-free or clean. A Washington State University study on the effects of damming conducted in a central European impounded river revealed that the reservoir reaches are a major source of methane emissions and that areal emission rates far exceed previous estimates for temperate reservoirs or rivers. It showed that sediment accumulation correlates with methane production and subsequent ebullitive release rates. Results suggested that sedimentation-driven methane emissions from dammed river hot spot sites can potentially increase global freshwater emissions by up to 7%. Hydroelectric facilities need to acknowledge and account for the associated GHG emissions they produce.
 Maeck, A., DelSontro, T., McGinnis, D.F, Fischer, H., Flury, S., Schmidt, M., Fietzek, P. and Lorke, A., 2013. Sediment Trapping by Dams Creates Methane Emission Hot Spots, Environmental Science and Technology, 8130-8137, Online: http://www.dx.doi.org/10.1021/es4003907
It is challenging to understand the logic of a November 2021 CBC article that reports, “The Nature Conservancy and the World Wildlife Fund are two environmental groups that oppose new hydro dams because they can block fish migration, harm water quality, damage surrounding ecosystems and release methane and CO2. But they say adding turbines to non-powered dams can be part of a shift toward low-impact hydro projects that can support expansion of solar and wind power.” Whether it’s a new dam or an older retrofitted dam, they will result in the same negative impacts and produce the same amount of methane for 70 to 100 years or more.
One of the most popular energy sources for Canada and globally has been hydroelectric power generation, and the provinces of Ontario, Quebec, Manitoba, and British Columbia are big fans of this particular energy source. One of the main reasons it is so popular is due to the abundance of water in Canada in the form of lakes and rivers that run throughout the provinces.
There was an article by the Montreal Gazette written back in 2011 that took a look at the Romaine River in Quebec and how it was about to turn into one of the biggest construction sites in Canada with the installation of 4 dams, 7 dikes, several large canals, and 279 square kilometers of reservoirs, all at the approximate cost of around $8 billion. What decision makers in Quebec failed to realize or choose to ignore is that harmful greenhouse gas (GHG) emissions are generated by reservoirs and they can be extensive and very damaging to the climate. Continue reading
June 18, 2014 — Water Institute Lecture Series and Faculty of Science Public Lecture Series
Dr. David W. Schindler, Killam Memorial Professor of Ecology, University of Alberta, retired.
Source: Washington State University
Researchers have documented an underappreciated suite of players in global warming: dams, the water reservoirs behind them, and surges of greenhouse gases as water levels go up and down. In separate studies, researchers saw methane levels jump 20- and 36-fold during drawdowns.
An excerpt from The Carbon Footprint of Water:
“Water is perhaps our most vital ecosystem service that our natural environment provides. As the inevitable impacts of climate change become evident, our freshwater resources and the ecosystems they support will become respectively less reliable and resilient. Smart water policies allow us to mitigate the worst aspects of global warming today, while the consequent improvements in water quality and river health will provide a critical buffer as humanity and nature adapt to the climate of tomorrow.”
The Conservation Law Foundation, a Boston-based environmental advocacy group, cited a report it commissioned from Synapse Energy Economics, that said the following: “The science is clear that the reservoirs behind hydropower dams emit greenhouse gases, relative to the forests and wetlands they flood (which often take greenhouse gases out of the atmosphere).
An excerpt from their Report:
“Hydroelectric generation of electricity (hydropower) is commonly thought of as renewable, sustainable, and lacking in emission of atmospheric pollutants; however, these assumed benefits are rarely evaluated critically in the context of policymaking, as new reservoirs and dams are rarely proposed in North America, outside of Québec and Labrador.
This report reviews the state of information regarding one key policy consideration: how hydropower stacks up against other technologies with respect to greenhouse gas (GHG) emissions—including the life cycle emissions from the construction and operation of generating capacity. An important aspect of the analysis is a comparison of not only the “typical” amount of GHG emissions from each technology, but a presentation of the range of values that may be observed. The report also discusses concerns about the way GHG emissions are measured, especially in the case of hydropower, and best practices for doing so. Finally, the report discusses a specific policy consideration: the relative trade-off (from a GHG emission perspective) of Canadian hydropower imports versus other energy options for New England.”
This is a must-read report that sheds a whole new light on the amount of water used to generate the wide range of sources used to generate power – you will be surprised.
An excerpt from the Report:
“It takes water to produce electricity. As many Americans retreat to air-conditioned environments to get out of the heat, the flame increases under our limited freshwater resources. The electrical energy used to create our comfort zones requires massive withdrawals of water from our rivers, lakes and aquifers to cool down nuclear, coal and natural gas power plants. Some of this water is evaporated while the majority of this water is warmed up—causing thermal pollution—killing aquatic life, increasing toxic algae blooms and decreasing the sustainability of our water supplies.”